Interchangeable compressor drive

ABSTRACT

A gear drive and a turbine drive are interchangeably connected to a compressor by means of compatible releasable fasteners between their respective housings and the compressor casing, and with identical releasable coupling means between the overhung compressor rotor and the output shaft of the gear drive or turbine wheel of the turbine drive. Thus, the sole bearing support for the rotor will be carried by the gear drive and the turbine drive. Accurate axial alignment of the compressor casing with the turbine drive and gear drive is obtained by means of abutting cylindrical surfaces of the drive housing and gear casing in telescopic engagement with an overlapping single cylindrical surface, which is preferably a fluid guide; for this purpose, the mounting of the drive housing is provided with radial play or radial adjustment. With the overhung rotor and removable barrel assembly comprising the fluid guide elements, the compressor rotor and fluid guide elements may be removed axially from one direction after uncoupling from the respective drive or axially in the other direction with the respective drive. The arrangement and selection of bearings cooperates with the selection of materials for the rotor, turbine wheel, housing and fluid guide elements to balance thermal expansion.

llnited States Patent [191 Pilarczyk 11] 3,809,493 [451 May 7,1974

[ 1 INTERCHANGEABLE COMPRESSOR DRIVE [75] Inventor: Karol Pilarczyk,Loudonville, NY. [73] Assignee: Carrier Corporation, Syracuse, NY.

[22] Filed: Nov. 29, 1971 [2]] Appl. No.: 202,849

Related US. Application Data [63] Continuation of Ser No. 44,403, June8, 1970.

415/122 R, 415/179 [51] Int. Cl. F04d 25/02, F04d 25/06, F04d 29/44 [58]Field of Search 4l5/l22, 199 A, 219 C, 415/110, 112; 417/406, 407, 374,405, 409

[56] References Cited UNITED STATES PATENTS 3,010,697 1l/1961 Lazo eta1. 417/407 1,903,210 3/1933 Carrier 415/122 2,480,435 8/1949 Aspelin415/199 A 2,695,131 11/1954 Price ..415/l22 2,888,193 5/1959 Greenwald.415/199 A 3,174,680 3/1965 Young 415/122 3,619,086 11/1971 Johnson415/122 FOREIGN PATENTS OR APPLICATIONS 917,976 9/1946 France 417/409497,922 12/1938 Great Britain..... 417 406 626,021 6/1947 Great Britain415/199 A 980,770 1/1951 France 415/122 at! \\\s\ k\\\\\\\\\\\\\\ V? Z\T%\W 4 E Primary Examiner-Henry F. Raduazo Attorney, Agent, orFirm-Harry G. Martin [5 7] ABSTRACT A gear drive and a turbine drive areinterchangeably connected to a compressor by means of compatiblereleasable fasteners between their respective housings and thecompressor casing, and with identical releasable coupling means betweenthe overhung compressor rotor and the output shaft of the gear drive orturbine wheel of the turbine drive. Thus, the sole bearing support forthe rotor will be carried by the gear drive and the turbine drive.Accurate axial alignment of the compressor casing with the turbine driveand gear drive is obtained by means of abutting cylindrical surfaces ofthe drive housing and gear casing in telescopic engagement with anoverlapping single cylindrical surface, which is preferably a fluidguide; for this purpose, the mounting of the drive housing is providedwith radial play or radial adjustment. With the overhung rotor andremovable barrel assembly comprising the fluid guide elements, thecompressor rotor and fluid guide elements may be removed axially fromone direction after uncoupling from the respective drive or axially inthe other direction with the respective drive. The arrangement andselection of bearings cooperates with the selection of materials for therotor, turbine wheel, housing and fluid guide elements to balancethermal expansion.

1 Claim, 3 Drawing Figures PATENTEDMAY 7 I974 SHEET 1 [1F 3 1INTERCHANGEABLE COMPRESSOR DRIVE This application is a continuation ofapplication Ser. No. 44,403 entitled Interchangeable Compressor Drive,"Karol Pilarczyk, inventor, filed June 8, 1970.

BACKGROUND OF THE INVENTION Compressors are required to be operated indifferent environments, which will determine the atmospheric conditionsor power sources available. For this reason, at many times it isdesirable to operate a compressor with a turbine drive or a gear drive.For example, if cheap electrical power is available a gear drive coupledto an electric. motor is desirable where if an explosive atmosphere ispresent a turbine drive with fluid controls would be most desirable.These drive requiremerits may change after a compressor has beenpurchased, which according to the prior art would require disposal ofexpensive equipment.

The interchangeability of drive units would be expected to createconsiderable problems with respect to alignment of the various parts.

CROSS REF ERENCING TO RELATED APPLICATIONS The features of the inventionof this application may be used in combination with the features of theinventions in applicants following related applications of the samefiling date and assignee as the present application, the disclosures ofwhich are incorporated herein in their entirety by, reference:fCompressor Barrel Assembly, Ser. No. 44,446 now issued as United StatesLetters Patent 3,7 17,418; Compressor Power Recovery, Ser. No. 44,463now issued as United States Letters Patent 3,680,973; Method of ChangingCapacity of Fluid Reaction Device, attorneys Ser. No. 44,263 now issuedas United States Letters Patent 3,664,001; Compressor Base andIntercoolers," Ser. No. 44,034 now issued as United States LettersPatent 3,644,054.

SUMMARY OF THE INVENTION The compressor of the present invention employsa gear drive and a turbine drive, each having housings that arereleasably fastened to the compressor casing of a compressor unitemploying an overhung rotor and fluidguide elements arranged as aremovable barrel assembly. Axial alignment between the drive housing andcompressor casing is obtained by means of abutting equal'diametercylindrical guide surfaces respectively on the compressor casing anddrive housing in telescopic engagement with a single cylindrical guidesurface, which is preferably on a fluid guide element. To further thisalignment, the drive housing is preferably mounted on the compressorbase with radial play or radial adjustment.

The compressor rotor is provided with a releasable coupling for rigiddriving engagement with the releasable couplingend of the gear unitoutput shaft and the turbine wheel shaft. In this manner, the drive unitmay be interchanged without disturbing the compressor unit and thecompressor unit may be withdrawn as a removable barrel withoutdisturbing the drive unit.

Further objects, features and advantages of the present invention willbecomemore clear from the follow- 7 s ta d st p o lstfiiels m 32' ferredembodiment of the present invention is specifi- V al y. !9 d BRIEFDESCRIPTION OF THE DRAWING FIG. 1 is a partial cross-sectional viewtaken in a vertical' plane passing through the axis of rotation of acomplete compressor assembly according to the present inventionincluding an electric motor and gear drive;

FIG. 2 is an enlarged cross-sectional view of a portion of FIG. 1; and

FIG. 3 is a view identical to FIG. 2, but with the turbine drive unitassembled.

DETAILED DESCRIPTION OF THE DRAWING As shown'in FIG. 1, a three-stagecentrifugal com pressor is provided with a base 1 rigidly mountingthereon by means of bolts or the like, a fluid inlet 2 having, an inletvalve 3 for controlling the passage of fluid to the compressor stages. Aone-piece cast iron compressor casing 4 is rigidly secured to the base 1and provided with a cylindrical opening having axially stacked annularair guiding elements 5, which cooperate with a single one-piece rotor 6.

The rotor is driven by means of an electric motor 7 that drives gearmeans 8 through the inter-position of a flexible coupling 9. When therotor 6 is driven,fluid enters through the inlet 2, is compressed in thefirst stage of the rotor and discharged through a first pas sage l0integrally cast in the casing 4. From the passage 10, the fluid passesdownwardly through an intercooler 11, upwardly through a demister l2,upwardly through a central passage (not shown) in the base 1 leading tothe second passage 13 cast in the casing 4 and finally to the inlet ofthe second stage. From the second stage the fluid is dischargeddownwardly through third passage 14 cast in the casing 4, downwardlythrought inter-cooler 15, upwardly through demister l6, upwardly throughcentral passage 17, up-

' wardly through fourth passage 18 cast in the casing 4,

and upwardly through the fluid guide elements 5 to thethird stage of therotor 6.

The gear means 8 are contained within a gear housing 19 that is bolteddirectly to the compressor casing 4 as will be explained in more detailhereafter. Preferably, the gear housing 19 is cast in one piece fromiron and the base 1 is welded, fabricated steel.

As shown more clearly in FIG. 2, the gear casing 19 has opposed sidewalls 20,21, which are provided with axially extending passages 22,23receiving therein high speed tilting pad-babitted face bearings 24,25,respectively. The bearings rotatably support an output shaft 26 thatdrivingly carries a pinion gear 27, which pinion gear 27 is in meshingengagement with a drive gear 28. As shown in FIG. 1, the drive gear 28is drivingly carried by an input shaft 29 rotatably mounted by opposedlow speed, sleeve babitted face bearings 30, 31. The outer axial end ofthe passage 23 is closed by means of a cover plate secured by bolts 33,with the interposition of a gasket 34, to the gear housing 19. The outerend of the axial passage 23 and the cover plate 32 form a lubricatingoil receiving chamber 35 draining through a passage 36 to the oil sumpof FIG. l.

The fluid guide elements 5 are most clearly shown in FIG. 2, and includethree axially stacked annular, aluminum fluid guides or diaphragms37,38,39, which are clampingly secured axially to the gear housing 19 bymeans of a fastener comprising a bolt 40 threaded into the gear housing19 at one end and provided with a nut 3 r a 41 at its other end. Thefluid guides 37, 38, 39 are telescopically received within'the'cylindrical portion of the compressor casing 4 for fluidv communicationwith the passages 10, 18, 14, 13. The fluid guide elements 5 furtherinclude shrouds 42, 43, 44 and diffusers 45, 46, 47, respectively forthe individual stages.

The rotor 6 has an axis of rotation axially aligned with the axis ofrotation -of output shaft 26, and further has a free terminal axial end48 and a coupling terminal axial end 49. At the coupling end 49, therotor 6,t elescopically receives the coupling end of output shaft 26,with a hydraulic shrink fit. This telescopic connection may be taperedand/or splined in any known manner so that it will provide anindependently rigid driving coupling that may be released withoutdestroying the respective parts. In this manner, it is seen that therotor 6 is cantilevermounted solely by means of its coupling end 49,which is rotatably carried by the output shaft 26, whichis in turnrotatably mounted by means of bearings 24, 25; thus, the bearings, 24,25 provide the only rotatable support bearings for the overhung rotor 6.The rotor 6 comprises a first-stage set of'peripherally arranged blades50, a second-stage of peripherally arranged blades 51, and a third-stageset of peripherally arranged blades 52. The entire rotor, includingblades 50, 51, 52, is constructed integrally in any known manner, forexample by casting in one piece, welding fabrication of the threepieces, or shrink fitting fabrication of three pieces. Preferably, therotor 6 is constructed of stainless steel and has labrinth interstageportions.

The compressor may be disassembled by removal of nut 41 and axialwithdrawal of the fluid guide elements 5 along with the rotor 6, whichmay be accomplished after the coupling at terminal end 49-is disengagedbetween output shaft 26 and rotor 6 through a central passage withinrotor 6 covered by a cap at the free terminal end 48 or the rotor 6 maybe removed with the output shaft 26, pinion 27 and bearings 24, 25secured thereto; in any event, the rotor and fluid guide elements 6, 5may be axially removed from the compressor casing 4 from the couplingend 49 toward the free terminal end 48. Similarly, these same elementsmay be removed in the other axial direction by removal of the bolts 53that secure the gear housing 19 to the .compressor casing 4. Thus, withremoval of these bolts 53 the gear casing 19,may be withdrawn totheright as shown in FIG. 2 to carry with it the gear means 8, the rotor 6and the fluidguideelements 5; with this withdrawal, the fluid inlet 2may remain untouched due to the telescopic connection illustrated.Alternately, the gear casing 19 may be removed by uncoupling the outputshaft 26 and rotor 6 at the coupling end 49 and removal of the bolts 53,40, without otherwise disturbing the rotor 6 and fluidguide elements 5.

For proper axial orientation of the gear means 8 and fluid guideelements 5, the bolt 53 is received within an oversize hole in the gearcasing 19, to provide for relative radial play and the axial alignmentbetween the I tween the gear housing 19 and base 1, or alternatively thebolts 53 may be eliminated and the gear housing supported solely by thebase 1 with radial clearance or shims. In any event, the axial alignmentbetween the gear housing 19 and compressor casing 4 is obtained byrespective axially aligned cylindrical guide surfaces overlapping withacylindrical guide member, with the cylindrical guide member preferablybeing a fluid guide. The single preferred embodiment of the presentinvention further includes a turbine drive unit for the rotor 6, whichis interchangeable with the previously described gear drive unit. Theturbine drive is shown specifically in FIG. 3. e t

In FIG. 3, all of the structural components bearing numerals identicalwith the numerals employed in FIG.

2 are correspondingly identical with the components of .FIG. 2.

fluid guide elements 5 or base 1 will be the same or compatible. And,the previous discussions with respect to axial alignment and varioustypes of mountings are applicable.

The turbine housing 55 is composed of two iron castings 56, 57 havingrespective axial passages in opposed walls for mounting the bearings 24,25; the castings 56, 57 being secured together by means of a bolt 58.

The bladed turbine wheel 59 is rotatably mounted by means of thebearings 24, 25 and has at one axial end releasable coupling meanscomplimentary to the releasable coupling means of rotor 6 at end 49. Thereleasable coupling means of the turbine wheel 59 is identical to thereleasable coupling means of the output shaft 26 of FIG. 2, iepreferably telescopically force fit engaging frusto conical surfaces,which might have alignment splines. Suitable turbine working fluidpassages are contained within the turbine housing 55, in a known manner.The actual turbine construction may be of any known type, but ispreferably centrigugal.

The compressor of the present invention is a high speed compressor witha direct turbine drive, which by its nature is of high speed, and a geardrive employing only two spur gears with a transmission ratio of 15to 1. With an electric motor operating at 3,600 rpms the compressorrotor would be driven at approximately 54,000 rpms. The advantage of asingle spur gear set, as appreciated with respect to compactness at sucha high speed,are readily seen. To enhance the meshing engagement in aknown manner, the gears 27,28 are provided with helical teeth, which areangled to offset the-net thrust produced by the three stages of therotor 6. The inter-cooperation between the gear drive and the turbinedrive is further seen by means of this thrust balancing in that thehelical gear teeth are matched to produce an axial thrust approximatelyequal to the expected axial thrust of the turbine bladed wheel 59. Inthis manner, the effect upon the rotor 6 of the gear drive and turbinedrive is substantially identical.

The present invention is so constructed that the net thermal expansion,in the axial direction, of the drive units is correspondingly equalbetween themselves and correlated tooffset the net thermal expansion, inthe axial direction, of the compressor unit rotor and stacked fluidguide elements. For this purpose, the turbine rotor, compressor rotorand gear drive unit output shaft are constructed of steel, with thecompressor rotor preferably being stainless steel, the turbine driveunit housing and gear drive unit housing are constructed of cast iron,and the fluid guide elements, including fluid guides, shrouds anddiffusers, are constructed of aluminum. The bearing arrangement is suchthat the outside bearing is the only thrust bearing for establishing thethermal expansion reference point to gain additional shaft length forexpansion purposes in offsetting the high expansion rates of thealuminum fluid guide elements that are subjected to high heat.Considerable expansion problems would be encountered if the insidebearing were a thrust bearing, because of the considerable differencebetween the expansion factors of the stainless steel'compressor rotorand the aluminum air guide elements taking into consideration thetemperatures involved; however,the additional expansion length gained bythe turbine rotor and output shaft 26 with location of the thrustbearing at the outside, the low expansion values of the cast ironrelatively cool drive unit housing are brought into play for theirconsiderable compensating effect. Thus, the gear drive unit and theturbine drive unit are matched with respect to thermal expansion for theembodiment of the present invention.

From the foregoing description it is seen that the complete embodimentof the present invention includes a compressor unit that may bereleasably coupled to a gear drive unit and a turbine drive unit, withthe understanding that the electric motor is not needed with the turbinedrive unit. This affords considerable versatility as the compressordrive may be adapted to the environment and changed as needs change.Further, it is seen that the releasable coupling between the compressorrotor and its drive provides for maximum flexibility and disassemblyfrom either axial direction for required servicing of either the driveor the compressor unit, or interchange of drive units.

Further, axial alignment is assured by axially aligned cylindricalabutting surfaces of the compressor casing and the drive unit housingtelescopically received on a single cylindrical guide surface, which ispreferably the outer cylindrical portion of the fluid guide 39. Thus,the accuracy needed for high speed operation is maintained.

Further, each of the drive units are so related that they will produce anet thrust to substantially equal the net thrust produced by thecompressor rotor, and so related that they will produce a net thermalexpansion substantially equal to the net thermal expansion of thecompressor rotor, and fluid guide elements.

While a single embodiment of the present invention has been described indetail for purposes of illustrating the invention, along withcontemplated variations, there is no intention to be limited solelythereto, as further embodiments, variations and modifications arecontemplated.

What is claimed is:

l. Fluid compression apparatus of the radial flow type comprising asubstantially cylindrical casing; a rotor positioned within the casing;a plurality of impellers mounted on the rotor; flow guide means arrangedwithin the casing including diaphragms, shrouds and diffusers positionedabout the impellers to define paths of fluid flow to and from theimpellers, said flow guide means being axially aligned to present asubstantially cylindrical outer surface complementary to the innersurface of the casing, the outer surface of the innermost member of theflow guide means extending axially beyond the casing to form a radialshoulder, and detachable closure and rotor drive shaft means includingbearing means assembled therein serving to support the rotor incantilever fashion, said drive means including rigid coupling means forconnecting the rotor to the drive shaft in axial alignment therewith,and-an annular flange encircling the radial shoulder formed by theaxially extending flow guide means while engaging the member of saidcasing, and means rigidly connecting the flow guide means to the closureand rotor drive shaft means said last-mentioned means including meanswhereby limited relative radial movement between the closure and rotorshaft drive means and the casing is obtained.

1. Fluid compression apparatus of the radial flow type comprising asubstantially cylindrical casing; a rotor positioned within the casing;a plurality of impellers mounted on the rotor; flow guide means arrangedwithin the casing including diaphragms, shrouds and diffusers positionedabout the impellers to define paths of fluid flow to and from theimpellers, said flow guide means being axially aligned to present asubstantially cylindrical outer surface complementary to the innersurface of the casing, the outer surface of the innermost member of theflow guide means extending axially beyond the casing to form a radialshoulder, and detachable closure and rotor drive shaft means includingbearing means assembled therein serving to support the rotor incantilever fashion, said drive means including rigid coupling means forconnecting the rotor to the drive shaft in axial alignment therewith,and an annular flange encircling the radial shoulder formed by theaxially extending flow guide means while engaging the member of saidcasing, and means rigidly connecting the flow guide means to the closureand rotor drive shaft means said last-mentioned means including meanswhereby limited relative radial movement between the closure and rotorshaft drive means and the casing is obtained.